It is strange that that map says the US debt is $14 trillion. It is over $18 trillion by now.
I checked the map. It is saying that all the countries have some debt, even the green ones. I wonder, then who is lending ? I mean, is there any country without a debt ?
p.s. Sorry, I'm not good in economics.
The first thing to know about governments, is that the government is not the people. The state, that is they, not us.
Governments loan from individuals in the area that is extended to the point where the next government is stronger, also called a country. They also loan from individuals in other countries. (They also loan from other governments, but that is not a part of the answer to your question).
Using currency manipulation, the governments move value from lenders to loaners, including themselves, but that does not change the fact that there is a lender somewhere for each loan.
All loans could in theory be paid back, extinguishing all debt. If the loaners are not able or willing to pay back, the loans could be written off as a loss, same result in the aggregate.
tl;dr Individuals are net lenders to governments.